Chemical analysis using low-field magnetic resonance

Abstract The composition of complex mixtures is often analyzed using high-field magnetic resonance (MR) spectroscopy, which typically relies upon large and expensive superconducting magnets. Here we introduce three methods based on low-field MR measurements which can be performed using inexpensive permanent magnets and are therefore advantageous for low-cost and portable applications. Firstly, relaxation and diffusion are known to be intimately related to molecular sizes and these relations have been formulated as scaling laws for mixtures of hydrocarbons. These scaling laws can be used for non-invasive determination of molecular size distributions. Secondly, we show that low-field J-coupling measurements can be used to identify different molecular moieties. Finally, we discuss low-field MR hardware and the development of a non-resonant sensor for improved Nuclear Quadrupole Resonance (NQR) spectroscopy. In summary, we show that low-field MR has the potential to be a powerful new tool for chemical analysis.